@graffy/common/src/decorate/decorateQuery.js

Common libraries that used by various Graffy modules.

import { isRange, isBranch } from '../node';
import { decodeKey } from '../encode';
import { keyStep } from '../graph';

function rangeToPage(key, end, count) {
  const page = {};
  page[count > 0 ? 'first' : 'last'] = count;
  if (key !== '') {
    const { key: k, step } = keyStep(key);
    page.after = decodeKey(k);
    if (step === 1) page.excludeAfter = true;
  }
  if (end !== '\uffff') {
    const { key: k, step } = keyStep(end);
    page.before = decodeKey(k);
    if (step === -1) page.excludeBefore = true;
  }
  return page;
}

export default function decorateQuery(query) {
  const result = decorateChildren(query);
  return result;
}

function decorateChildren(query) {
  const isPage = query.some((node) => isRange(node));
  if (isPage) {
    return decoratePage(query);
  } else {
    return decorateBranch(query);
  }
}

function decoratePage(query) {
  const result = [];
  for (const node of query) {
    const child = isBranch(node) ? decorateChildren(node.children) : true;
    if (isRange(node)) {
      const { key, end, count } = node;
      result.push(rangeToPage(key, end, count), child);
    } else {
      const { key } = node;
      result.push(rangeToPage(key, key, 1), child);
    }
  }

  return result;
}

function decorateBranch(query) {
  const result = {};
  for (const node of query) {
    const child = isBranch(node) ? decorateChildren(node.children) : true;
    const { key } = node;
    result[key] = child;
  }
  return result;
}